1,2,3,4-tetracarboxylic acid anhydride

Another group of polymers with good heat resistance includes certain aryl-alicyclic compounds. They are generated from the polycondensation of 4,4 -diaminodiphenyl oxide with various anhydrides such as tricyclo[4,2,2,0 ]dec-9-ene-3,4,7,8-tetracarboxylic acid anhydride, 9-oxatricyclo[4.2,2,0 ]nonane-3.4,7,8-tetracarboxylic acid anhydride, cyclobutene-1,2,3,4-tetracarboxylic acid anhydride, and bicyclo[2,2,2]octane-23,5,6-tetracarboxylic acid anhydride. Thermal stability of these polymers is affected by the ring stability (strain) regardless the true chemical structure. Pyrolysis at 650° C generates some compounds that are the same in nature and some others that are characteristic for each polymer. The main decomposition paths, as indicated by the main pyrolysis products are shown below for each polymer (Ar = 4,4 -diphenylene oxide) ... 

The 13C spectra of various cycloalkane tetracarboxylic acid anhydrides have been examined. In the cyclobuta-fused compounds, the carbonyl carbon atoms appear at relatively higher values than in larger systems <92CA(116)83109). 

The majority of polynaphthylimides described in literature results from the interaction of naphthalene-1,4,5,8-tetracarboxylic acid anhydride with various diamines [156]. In addition, a series of bis(naphthalic anhydrides) with hinge groupings was employed in synthesis of polynaphthylimides. In particular, the... 

Some polymeric materials are completely free from hydrogens. An example is polysulfodia-zole a lyimide prepared from pyrazine-l,2,4,5-tetracarboxylic acid anhydride and diami-nothiazine. ... 

The extension of this reaction to tetrafunctional monomers (e.g., pyromelittic acid anhydride or benzophenone tetracarboxylic acid anhydride), results in the formation of polyimides. 

All of the above materials maintain useful properties up to 300°C in air and can be formed into fibers. Some polymeric materials are completely free from hydrogens. An example is polysulfodiazole [212], a polyimide prepared from pyrazine-l,2,4,5-tetracarboxylic acid anhydride and diaminothiazine [213]. This material exhibits particularly good heat stability [213] ... 

Polyimides (Figure 2.58) are typically prepared by reacting a tetracarboxylic acid anhydride such as pyromellitic dianhydride with aromatic diamines such as 4,4 -diaminodiphenylether. Heat... 

The use of tetracarboxylic acid anhydride instead of the dicarboxylic acids used in the manufacture of polyamides yields polyimides. The general method of preparation of the original polyimides by the polymerization of pyromellitic dianhydride and aromatic diamine is shown in Figure 1.18a. A number of diamines have been investigated, and it has been found that certain aromatic amines, which include m-phenylendediamine, benzidine, and di-(4-aminophenyl)ether, give polymers with a high degree of oxidative and thermal stability. 

Naphthalene-1,8-dicarboxylic add, its nitro-substituted derivatives, and naphthalene-1,4,5,8 tetracarboxylic acid, on treatment with sulfur tetrafluoride at 0 C, undergo dehydration to form quantitatively the corresponding anhydrides [218, 221] Unsubstituted and mononitrated monoanhydndes react further at 200-250 °C to give derivatives of 1,1,3,3-tetrafluoro-l// naphtho[I,8 c,d]pyran Dinitronaphthalene-l,8-di-carboxyhc acid anhydndes and naphthalene 1,4,5,8 tetracarboxylic acid dianhydnde give the respective tetra- and octafluoroethers only in the presence of an excess of anhydrous hydrogen fluoride [221] (equabons 113 and 114)... 

Perylenes (70) are diimides of perylene-3,4,9,10-tetracarboxylic acid, and may be prepared by reaction of the bis-anhydride of this acid, 89 (1 mol) with the appropriate amine (2 mol) in a high-boiling solvent as illustrated in Scheme 4.11. The synthesis of perinones 71 and 72 involves condensation of naphthalene-1,4,5,8-tetracarboxylic acid with benzene-1,2-diamine in refluxing acetic acid. This affords a mixture of the two isomers, which may be separated by a variety of methods, generally involving their differential solubility in acids and alkalis. 

The synthetic route to perinone pigments, as to perylene pigments, starts from an anhydride, in this case from the monoanhydride of naphthalene tetracarboxylic acid. 

Ethane-tetracarboxylic Acid Dianhydride, [3,7-Dioxa-2,4,6,8 tetra-oxo-bicyclo(3,3,0)-octane], mw 170.1, OB to COg —66%, cryst, dec over 150°. It was first prepd in 1920 by heating the acid in a six-fold excess of acetic anhydride at 70—75°, then in 1923 by treating the acid with AcCl and heat, or by treating with oxalyl chloride, the acid or the tetra-silver salt of the acid (Ref 6)... 

Decarboxylation reactions of cyclobutanecarboxylic acids appear to pose no particular problems. Cyclobutane-1,1-dicarboxylic acids can usually be decarboxylated thermally at temperatures up to 200 C.1 5> n 340 For example, cyclobutane-1,1,3,3-tetracarboxylic acid was heated to 185 °C at reduced pressure to give a mixture of cis- and frani-cyclobutane-l,3-dicarboxylic acid (l).1 Noteworthy in this reaction is the stereocontrof obtained in the product due to the formation of the anhydride. Generally, decarboxylation will give a mixture of cis- and transacids. The decarboxylation has sometimes been performed in a distillation step.4,5... 

Initially, water can cause the hydrolysis of the anhydride or the isocyanate, Scheme 28 (reaction 1 and 2), although the isocyanate hydrolysis has been reported to occur much more rapidly [99]. The hydrolyzed isocyanate (car-bamic acid) may then react further with another isocyanate to yield a urea derivative, see Scheme 28 (reaction 3). Either hydrolysis product, carbamic acid or diacid, can then react with isocyanate to form a mixed carbamic carboxylic anhydride, see Scheme 28 (reactions 4 and 5, respectively). The mixed anhydride is believed to represent the major reaction intermediate in addition to the seven-mem bered cyclic intermediate, which upon heating lose C02 to form the desired imide. The formation of the urea derivative, Scheme 28 (reaction 3), does not constitute a molecular weight limiting side-reaction, since it too has been reported to react with anhydride to form imide [100], These reactions, as a whole, would explain the reported reactivity of isocyanates with diesters of tetracarboxylic acids and with mixtures of anhydride as well as tetracarboxylic acid and tetracarboxylic acid diesters [101, 102]. In these cases, tertiary amines are also utilized to catalyze the reaction. Based on these reports, the overall reaction schematic of diisocyanates with tetracarboxylic acid derivatives can thus be illustrated in an idealized fashion as shown in Scheme 29. 

The synthesis of the poly-(o-chlorophenyl)-imides was accomplished in two steps involving low-temperature reaction between the diamines and bis(phthalic anhydrides) in NMP followed by catalytic imidisation of the PCA directly in the reaction solutions using the catalytic complex pyridine acetic anhydride. The synthesis of polyimides from l,l-dichloro-2,2-di-(3-amino-4-aminophenyl)-ethylene proceeded homogeneously throughout the course of the reaction, as did reactions of 3,3 -diamino-4,4 -dichlorobenzophenone with the dianhydride of diphenyloxide-3,3, 4,4 -tetracarboxylic acid. As to reactions of 3,3 -diamino-4,4 -dichlorobenzophenone with the dianhydrides of pyromellitic and diphenylsulfone-3,3, 4,4 -tetracarboxylic acids, these were homogeneous at the PCA formation step but heterogeneous at the polyimide formation step. Some properties of these polyimides are given in Tables 3.3 and 3.4. 

For thermal stability polypyromellitimides are somewhat inferior to polyimides based on the anhydrides of other aromatic tetracarboxylic acids. This is apparently due to the higher chlorine content per unit polymer weight in the former. 

Room temperature interaction of the diamines and tetracarboxylic acid dianhydrides, in NMP, leading to the formation of poly(o-carboxy)-amides followed by catalytic imidisation of these polymers with pyridine-acetic anhydride complex. 

When the reaction mixtures were heated for several hours, mixtures of tellurium tetrakis[2,2,3,3-tetrafluoropropoxide] and five molar equivalents of carboxylic acid anhydrides produced tellurium tetracarboxylates. The crystalline products were washed with hexane-benzene (1 1) and dried in vacuo1. 

On an industrial scale, the traditional method for cleavage of carbon-carbon double bonds is ozonolysis, used for the manufacture of azelaic acid and nonanoic acids from oleic acid, and of butane tetracarboxylic acid from tetrahydrophthalic anhydride. The process is effectively a quantitative and mild process.178 However, it is capital and energy intensive. The intermediate ozonide is worked up either reductively or oxidatively to produce the aldehyde, ketone or carboxylic acid. Hydrogen peroxide is the common oxidizing agent used in the second step.179-181 Oxygen can also be used either alone182 or in combination with zeolites.183 Reviews on ozonolysis are available and the reader is directed to reference 184 for further information. 

A number of carboxylic anhydrides have been converted into trifluoromethyl compounds by treatment with sulfur tetrafluoride, usually in the presence of hydrogen fluoride. As in the case of carboxylic esters, vigorous conditions are needed. Some examples have been presented in Houbcn-Weyl, Vol. 5/3, pp 92, 93. Depending on the reaction conditions, different compounds can be isolated. In some, cyclic di- or tetrafluorinated ethers predominate. 1.253.254 Upon reaction with sulfur tetrafluoride/hydrogen fluoride, pyromellitic dianhydride, as well as pyromellitic acid (benzcnc-l,2,4,5-tetracarboxylic acid), gives a mixture of 1,2,4,5-tet-rakis(trifluoromethyl)bcnzcne, 1,1,3,3-tetrafluoro-5,6-bis( trifluoromethyl)- ,3-dihydroisoben-zofuran, and the fully fluorinated tetrahydrobenzodifuran in an 85-88 10-13.5 1-2 ratio (see formation of compounds 13-15, vide supra)d ... 

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